A ventilator generally includes a fan and a set of controls. The controls generally comprise a switch to select various operating speeds, for example but not limited to low, medium, high, etc. and a dehumidistat. The dehumidistat sets the level of relative humidity that will trigger the ventilator to operate at the speed set by the switch.
The ventilator uses the fan to extract humid air, for example, from a basement location and send the extracted humid air to the outside environment, and allows air to be vented from the main floor and into the basement. The air coming from the main floor is generally supplied by fresh air coming in from outside the house.
In ideal situations, the humidity level of the incoming air is lower than the humidity of the original air in the basement. Over time, this will ensure a gradual reduction of the relative humidity level in the basement. However, a problem arises when the incoming air has high levels of humidity. It is undesirable to transfer this humid air from the main floor to the basement as it will increase the relative humidity in the basement.
As described above, the user has access to a switch which controls the ventilator by manually setting the fan speed and a dehumidistat to select the humidity level which will trigger the ventilator to operate. Both these control methods allow the user to prevent the machine from operating in undesirable conditions, such as high humidity. These changes need to be made manually, therefore if the user is not present to make the changes, the ventilator will keep running at its set values.